The disclosure is directed to a compact and robust two-color image-on-image (IOI) universal marking module in a xerographic marking device.
Several different color printing technologies have emerged in recent years. Early color xerography was accomplished by developing single color images onto a photoreceptor drum and then performing individual transfers of the single color images onto a substrate, such as paper, or onto an intermediate material, to build up a full color image. Xerox products using this technology included models 6500, 5775, and DC12. To improve quality, two particular competing marking architecture technologies were developed: tandem and image-on-image (IOI) technologies. The fundamental difference between the tandem and IOI architectures is where the four-color image is constructed. In a typical IOI architecture, the four-color image is constructed on one photoreceptor and transferred in a single step to a substrate. An example of a printer employing this architecture is the iGen3 series of marking engines made by Xerox Corporation. The multiple charge, expose and development steps on a single photoreceptor and the transfer of all four color toners in a single step offer advantages, while the complex system interactions resulting from such steps add complexities in control of the charge, development and exposure.
In tandem architectures, the IOI complexities are generally avoided by separating the process into multiple steps. In a typical tandem architecture, the four-color image is constructed either on paper or an intermediate transfer member. Each color toner is transferred separately from an individual photoreceptor to the paper substrate, either directly or through the intermediate member. Examples of tandem architecture included Xerox models DC250 and DC8000. While tandem architectures have fewer image-on-image type system interactions and the interactions are less severe, one has to manage multiple toner transfers and registration steps with a larger number of components. Tandem architectures thus generally require high speed motion control systems to reduce registration errors and other motion errors. Thus, there are advantages and disadvantages to each architectural system. For a more detailed explanation and comparison of such architectures, one can review a publication entitled “Is Image-On-Image Color Printing a Privileged Printing Architecture for Production Digital Printing Applications?” by Rick Lux et al., the disclosure of which is incorporated by reference herein in its entirety.